When anaesthetic gases are used in a hospital environment, such as for example in an emergency or operating room, the halogenated agents from the gases or the exhalent of the patient have to be purged from the immediate enclosed environment to protect the people in that enclosed environment. To achieve this purging of the halogenated agents, the patient, and the anesthetic machine to which the patient most likely is attached, are connected to a scavenging system whereby the halogenated gases are exhausted to the outside environment away from the enclosed operating room. Oftentimes, N2O is also used in an operating room.
To remove the anesthetic gases from the exhalent of a patient, there has been disclosed in the prior art the use of an adsorbent unit in the form of disposable cartridges (U.S. Pat. No. 3,941,573, U.S. Pat. No. 3,867,936 and U.S. Pat. No. 5,044,363) in which the patient's exhalent is adsorbed. These disposable cartridges contain adsorbent fillers that react with and absorb the halogenated gases. As the amount of anesthetic gases is absorbed, the material in the disposable cartridges or containers saturates and the cartridges would increase in weight and as a consequence will no longer adsorb the anesthetic gases after a given time. Thus, after a certain amount of time or after the cartridges reach a certain weight, these cartridges are replaced with new cartridges.
There has also been disclosed in the prior art (U.S. Pat. No. 5,231,980) a process for recovering the halogenated hydrocarbons from a patient's exhalent. To accomplish this, the '980 patent discloses the use of a sensor at the exhaust line to sense the presence of anesthetics exiting from the cannister that adsorbs the halogenated hydrocarbons. The sensor may be connected by a signal line to the anesthesia machine to provide an indication to the anesthetist that the adsorbent cannister should be replaced so that the recovery of the anesthetics could continue. For the device disclosed in the '980 patent, the cannister has to be connected to the anaesthesia machine by both a gas line and a signal line. Insofar as the cannister has to be connected to the anesthesia machine, it is considered as part of the anesthesia machine and accordingly is cumbersome and not meant for portability.
A need therefore exists for a portable standalone system that has a replaceable cannister adaptable for adsorbing halogenated agents. The portable standalone system could be used in any environment, including an enclosed room in which halogenated hydrocarbons may be released from the exhalent of a patient.
The present invention detection device is used where it is not possible to vent the anesthetic gases directly into an operating room, since doing so would cause the air in the operating room to exceed OSHA limits in a relatively short period of time, as for example 10 minutes in the instance where the operating room is a small room in a field hospital, or a veterinary operating room where a veterinarian is treating an animal.